If you slosh water in a bathtub at the correct frequency, the water rises first at one end and then at the...?

Question

If you slosh water in a bathtub at the correct frequency, the water rises first at one end and then at the other. Suppose you can make a standing wave in a 150 cm long tub with a frequency of 0.30 Hz. What is the velocity of the water wave?

Please help me with this problem
I don't understand it.

Answer 1

A standing wave means that there are an exact number of half wavelengths. So you set up the equation n (lamda/2) = 150cm. you solve for lamda and multiply by the frequency, thus you can not know the velocity, only a selection of possible ones.